Crystalline Fe- and Co-based foams are known and have been produced using known methods, such as generating gas bubbles, powder metallurgy, etc. However, the molten states of crystalline metallic alloys exhibit rather low viscosities, typically on the order of 10−3 Pa-s. Consequently, efforts to produce crystalline metal foams by generating gas bubbles are severely hindered by the tendency of bubbles to sediment. Powder metallurgical routes may also be used, which involves bubble generation within a powder matrix of the metal. These routes improve the overall homogeneity of the porous product. Other methods are also used for reducing bubble sedimentation. One such method involves the introduction of stabilizing substances into the melt. Another method involves the generation of bubbles in the semi-solid state.